Parasitology Sporozoons

ParasitologySporozoons1Parasitology/Sporozoons (3 hours)1.Defines Sporozoon1.1 Lists the sporozoon classification.1.2. Defines the cell structure of sporozoons.1.3. Defines the life cyles of sporozoons; lists the cysts, trophozoits, oocysts, promastigot, amastigot structures.

2.Lists the clinical tables related with sporozoons and defines pathogenetic mechanisms.2.1. Defines the clinical importance of sporozoons.2.2. Defines the sample taking related with infections of sporozoons.2.3. Lists the laboratory diagnostic methods.

FlagellatesIntestinal flagellatesGiardia intestinalisTrichomonas sppDientamoeba fragilis

Trichomonas vaginalis

HemoflagellatesLeishmania donovaniTrypanosoma cruzi

Giardia intestinalis (lamblia)Cysts are resistant forms and are responsible for transmission of giardiasis.Both cysts and trophozoites can be found in the feces (diagnostic stages) The cysts are hardy and can survive several months in cold water.Infection occurs by the ingestion of cysts in contaminated water, food, or by the fecal-oral route (hands or fomites) Because the cysts are infectious when passed in the stool or shortly afterward, person-to-person transmission is possible

Symptomsdiarrhea, abdominal pain,bloating, nausea, vomiting. incubation period: 1 to 14 days (average of 7 days) Diagnosiscysts or trophozoites in the feces, using direct mounts(repeated samplings)

samples of duodenal fluid (e.g., Enterotest)

duodenal biopsy may demonstrate trophozoites

alternate methods antigen detection tests enzyme immunoassays,detection of parasites by immunofluorescence.

Trichomonas vaginalisresides in the female lower genital tract and the male urethra and prostate transmitted among humans, its only known host, primarily by sexual intercourse no cyst formation

Symptomsvaginitis with a purulent discharge is the prominent symptom, vulvar and cervical lesions, abdominal pain, dysuria dyspareunia. In men asymptomatic; urethritis,epididymitis,prostatitis the incubation period is 5 to 28 days.Diagnosismicroscopic examination of wet mounts culture

Dientomoeba fragilisnot an ameba but a flagellate no cyst formation

Symptomsdiarrhea, abdominal pain,anorexia,nausea, vomiting, fatigue,weight loss. Diagnosisdetection of trophozoites in permanently stained fecal smears (e.g., trichrome).not detectable by stool concentration methods.trophozoites can be easily overlooked ,they are pale-staining and their nuclei may resemble those of Endolimax nana or Entamoeba hartmanni.

Leishmania donovania vector-borne diseasetransmitted by sandfliescaused by obligate intracellular protozoa of the genus Leishmania

Promastigotes amastigotes in the sandfly's midgut, the parasites differentiate into promastigotes in MexicoCentral America, South Americasouthern Europe Asia (not Southeast Asia),the Middle East, and Africa SymptomsCutaneous leishmaniasis (L.tropica)one or more sores on their skin.the sores can change in size and appearance over time. they often end up looking somewhat like a volcano, with a raised edge and central crater. a scab covers some sores.

the sores can be painless or painful. some people have swollen glands near the sores (for example, in the armpit if the sores are on the arm or hand). SymptomsVisceral leishmaniasis (kala-azar)(L.donovani)

fever, weight loss, enlarged spleen and liver (usually the spleen is bigger than the liver).Some patients have swollen glands. Certain blood tests are abnormal. low blood counts, including a low red blood cell count (anemia), low white blood cell count, and low platelet count.Some patients develop post kala-azar dermal leishmaniasis.Visceral leishmaniasis is becoming an important opportunistic infection in areas where it coexists with HIV.

DiagnosisGiemsa-stained slides culture (using for example the diphasic NNN medium) Antibody detection

Trypanosoma cruzi Chagas disease,a zoonotic disease transmitted to humansby blood-sucking triatomine bugs (kissing bug)

Chronic Chagas disease is a major health problem in many Latin American countries

trypomastigotes amastigotes trypomastigotes amastigotes Trypanosoma cruzi can also be transmitted throughblood transfusions, organ transplantation, transplacentally, in laboratory accidents. Symptomsfever,anorexia, lymphadenopathy, mild hepatosplenomegaly, myocarditis. Chronic stage may not occur for years or even decades after initialinfection. cardiomyopathy (the most serious manifestation); megaesophagusmegacolon; weight loss.Chronic Chagas disease and its complications can be fatal. DiagnosisMicroscopic examination:of fresh anticoagulated blood, or its buffy coat, for motile parasites;of thin and thick blood smears stained with Giemsa, for visualization of parasites.

Isolation of the agent by: inoculation into mice; culture in specialized media (e.g. NNN, LIT); xenodiagnosis, where uninfected reduviid bugs are fed on the patient's blood, and their gut contents examined for parasites 4 weeks later.

Treatmentbenznidazole or nifurtimox In the chronic stage, e.g., pacemaker for heart block Trypanosoma brucei T. b. gambiense -West African sleeping sicknessT. b. rhodesiense - East African sleeping sickness. T. b. brucei - under normal conditions does not infect humans

tsetse fly (genus Glossina)

Symptomsa trypanosomal chancre can develop on the site of inoculation.a hemolymphatic stage (fever, lymphadenopathy, and pruritus.)the meningoencephalitic stage ( headaches, somnolence, abnormal behavior, loss of consciousness and coma)the course of infection is much more acute with T. b. rhodesiense than T. b. gambiense. Diagnosismicroscopic examination of chancre fluid, lymph node aspirates, blood, bone marrow, or, in the late stages of infection, cerebrospinal fluid.a wet preparation should be examined for the motile trypanosomes, and in addition a smear should be fixed, stained with Giemsa (or Field), and examined. the Card Agglutination Trypanosomiasis Test (CATT) test is of value for epidemiologic surveys or screening of T. b. gambiense

AmebasIntestinal amebasEntamoeba histolyticaEntamoeba coliBalantidium coli

Free-living amebasNaegleria fowleriAcanthamoeba castellani

AmebiasisEntemoeba histolyticaEntemoeba coliEntemoeba hartmanni

Symptomsasymptomatic infection ("luminal amebiasis"), invasive intestinal amebiasis dysentery, colitis, appendicitis,toxic megacolon, amebomas, invasive extraintestinal amebiasis liver abscess,peritonitis,pleuropulmonary abscess,cutaneous genital amebic lesions DiagnosisFresh stool: wet mounts and permanently stained preparations (e.g., trichrome). Concentrates from fresh stool: wet mounts, with or without iodine stain, and permanently stained preparations (e.g., trichrome). Concentration procedures, however, are not useful for demonstrating trophozoites. E. histolytica trophozoites can also be identified in aspirates or biopsy samples obtained during colonoscopy or surgery Erythrophagocytosis is the only morphologic characteristic that can be used to differentiate E. histolytica from the nonpathogenic E. dispar

E.histolytica trophozoites

E.histolytica cysts

E.coli trophozoites

E.coli cysts

E.hartmanniBalantidum colia large ciliated protozoan parasite Most cases are asymptomatic.Clinical manifestationspersistent diarrhea, occasionally dysentery, abdominal pain, weight loss.

Diagnosistrophozoites in stool specimens or in tissue collected during endoscopy. Cysts are less frequently encountered.

Balantidium coli trophozoitestheir large size (40 m to more than 70 m). the presence of cilia on the cell surface,a bean shaped macronucleus which is often visible, a smaller, less conspicuous micronucleus.

Naegleria fowleri - Acanthomoeba sppcommonly found in lakes, swimming pools, tap water, and heating and air conditioning units.only one species of Naegleria is known to infect humans, several species of Acanthamoeba are implicated

SymptomsAcute primary amebic meningoencephalitis (PAM) - Naegleria fowleri.severe headache and other meningeal signs, fever, vomiting, and focal neurologic deficits, and progresses rapidly (